Let's face it...no one enjoys cleaning the litter box! When I was pregnant, I had absolutely no problem with letting my husband take over the nasty job. But, what that really necessary? Read on to find out!

Toxoplasmosis

The reason for all of the worry is a protozoan parasite called toxoplasmosis. Normally, if a person gets infected with toxoplasmosis they can get some of the following symptoms:

fever

swollen lymph nodes

muscle pain

swollen spleen (causing abdominal pain)

swollen liver

Often, the symptoms are very mild and are similar to a virus such as a cold. However, if a pregnant woman gets toxoplasmosis then there are several risks to the fetus including:

miscarriage

stillbirth

blindness

mental retardation

hydrocephalus (fluid on the brain)

microcephalus (brain is too small)

How does a human get toxoplasmosis?

You would think that the most common place for a woman to pick up toxoplasmosis is from a cat. However, this type of transmission does not happen often. The most common way for a person to get toxo is to ingest raw or poorly cooked meat from an animal that has toxoplasmosis cysts in their muscle. The most common types of meat that can carry toxoplasmosis are lamb or pork.

Your cat can get toxoplasmosis from eating raw meat (including mice). If a cat ate a mouse who had toxo cysts in its muscle then the cat can end up getting toxo. If a cat gets the organism they can shed toxoplasmosis cysts in their feces for about 5 to 14 days. After 24-48 hours, these cysts can become infectious to people. If a cat gets toxo a second time, they do not tend to shed cysts are are not infectious.

In order for a pregnant woman to get toxoplasmosis from a cat there are three ways for this to happen:

She could ingest some of the stool from a cat who is shedding cysts. (i.e. the cat itself became infected 5-14 days before.) The stool would have to be 24-48 hours old.

If the stool was really old and dry, it's possible that toxoplasmosis cysts could be inhaled. (Again, the cat would have to have been infected 5-14 days earlier).

If the cat was infected and she ate the cat raw, she could get infected. (Yeah, I know, that's silly).

One other possible source of toxoplasmosis is from soil that has contained infected cat feces. It is possible to get infected by gardening, getting cat feces on your hands, and not properly washing your hands before eating. Similarly, if vegetables were grown in the soil and they came in contact with the cat feces, then if they were eaten without being washed, toxoplasmosis cysts could be ingested.

Toxoplasmosis is most dangerous if picked up during the first trimester, but can affect the fetus at any stage in pregnancy.

What happens if your cat has a positive blood test for toxo?

I don't recommend testing a cat for toxoplasmosis because the results don't really tell us anything. If a cat has a positive toxo test, this means that he is already infected and is not likely shedding cysts. (Therefore, he's not contagious. Remember, the cat only sheds the organisms during the period of 5 to 14 days after eating the infected meat.)

A negative toxo test doesn't tell us much because the cat could still get infected at any point if he eats an infected piece of meat. (But, keep in mind that this is quite rare.)

Do mice shed toxoplasmosis in their feces?

When I initially posted about this article on my Facebook Page, one of my readers asked an interesting question. Could a person get toxoplasmosis from ingesting mouse feces? The answer is no, and this is why:

There are two types of hosts for toxoplasmosis: definitive and intermediate.

Only definitive hosts can shed toxoplasmosis in their feces.

Any mammal or bird can be an intermediate host (and therefore can store cysts in their muscle). These animals can spread toxoplasmosis if their flesh is eaten without being properly cooked.

The only definitive host for toxoplasmosis is a cat. Therefore, cats are the only animals that can spread toxoplasmosis in their feces. Mice (or any other animal) cannot.

So, should a pregnant woman avoid cleaning the litter box?

While the chances of a pregnant woman getting toxoplasmosis from cleaning out the litter box are small, it's still a good idea to have someone else clean the box if possible. If you do not have someone else to clean the box, you can take the following precautions:

Clean the litter box twice daily. (The cysts are only contagious after they have been out of the cat for 24-48 hours.)

Wash your hands after cleaning the box.

Avoid gardening outside (where there may be cat feces present), or wear gloves.

Do not eat undercooked meat.

Surprising statistics!

When I first wrote this article I was under the assumption that a woman getting toxoplasmosis was extremely rare. However, some research shows that 23% of the North American population has been exposed to toxoplasmosis. (Most likely the vast majority of these cases did not come from cats, but rather from eating undercooked meat.)

Remember though, that toxo is only dangerous to a pregnancy if a woman picks it up during her pregnancy. If you already have a positive toxo titer, this is a good thing. It's only women with no previous exposure who are at risk.

It is difficult to find numbers on the incidence of birth defects or stillbirths caused by toxoplasmosis because it is not a condition that doctors are required to report. I have read that anywhere from 1 in 1000 to 1 in 10000 births are affected by toxoplasmosis. This is actually a much higher number than I expected!

Should you get rid of your cat if you are pregnant?

Occasionally I have seen families who have decided that they need to get rid of their cat because they are worried about the risk of toxoplasmosis. This is really not necessary. Take the precautions listed above and the chances of infection are almost none.

Remember, the most common source of toxoplasmosis infection is eating undercooked meat, especially lamb and pork.

And by the way...

My daughter is now a grown girl and my husband still cleans the litter boxes in our house. This was a good habit to start!

Dr. Marie is a veterinarian who practices in a busy animal hospital in Ottawa, Ontario. She created Ask A Vet Question as a resource for good, accurate veterinary advice online. Dr. Marie treats dogs, cats, hamsters, guinea pigs, and rats. She has been a vet since 1999.

Is an online vet visit just as good as a trip to your veterinarian? No! But, many times, asking an online veterinarian a question can help save you money. While Dr. Marie can't officially diagnose your pet or prescribe medications, she can often advise you on whether a vet visit is necessary. You can also ask Dr. Marie for a second opinion on your pet's condition.